A bit patterned medium is well known. The bit patterned medium allows recordation of bit data in each of magnetic dots arranged in a nonmagnetic body. Photolithography is utilized to establish the magnetic dots. A photoresist is subjected to exposure on the disk-shaped substrate. Electron beam is utilized to expose the photoresist. The electron beam is intermittently applied in accordance with predetermined clock signals. The sequence of beam spots realizes the exposure of the photoresist. The electron beam lithography allows exposure for every beam spot. The magnetic dots are formed based on a set of the beam spots.
Burst patterns made of magnetic dots are well known. The burst patterns are arranged at predetermined intervals in the circumferential direction. The individual burst pattern includes magnetic dots arranged in a nonmagnetic body in a predetermined repetitive pattern repeated in the radial direction. The phases of the repetitive patterns are synchronized with one another for all the burst patterns. This results in alignment of the intervals between the magnetic dots in the burst patterns on an arbitrary circumferential line. A magnetic head cannot output a read signal having a sufficient intensity above the circumferential line. The tracking servo control of the magnetic head cannot be performed with a sufficient accuracy.